1. Technical Field
The present invention relates to a method of manufacturing a printed circuit board having intaglio circuit patterns.
2. Description of the Related Art
With developments in electronic components, fine-line circuit wiring is being employed, in order to provide higher densities in the printed circuit board. This, however, can result in lower adhesion between the metal circuit lines and the insulation, which may cause problems such as the circuit lines being peeled off from the insulation. To improve this, a technique is under development, which includes processing an intaglio groove in the insulation and then filling the groove with metal by a plating process.
The filling of a metal by plating into an intaglio groove having a small width may not pose serious problems even when existing chemicals and processes are employed, but in cases where the width is large, such as the case illustrated in FIG. 1, it can be difficult to obtain a uniform plating thickness using existing techniques, compared to the cases for narrow intaglio grooves. Thus, it may be difficult to obtain a faultless wide circuit pattern 112 without employing a separate leveling process. When an etching process is applied to a plated circuit pattern 112, the inner portion of the intaglio groove can become uncovered, as illustrated in the drawing on the right in FIG. 1.